Download presentation

1
**Register Transfer and Microoperations Part2**

2
**4.5 Logic Microoperations**

Manipulating the bits stored in a register Logic Microoperations 2

3
**Clear Logic operation can…**

clear a group of bit values (Anding the bits to be cleared with zeros) R1 (data) R2 (mask) R1

4
Set set a group of bit values (Oring the bits to be set to ones with ones) R1 (data) R2 (mask) R1

5
Complement Complement a group of bit values (Exclusively Or (XOR) the bits to be complemented with ones) R1 (data) R2 (mask) R1

6
LOGIC CIRCUIT • A variety of logic gates are inserted for each bit of registers. Different bitwise logical operations are selected by select signals. 6

7
Example Extend the previous logic circuit to accommodate XNOR, NAND, NOR, and the complement of the second input. S2 S1 S0 Output Operation X Y AND 1 X Y OR X Å Y XOR A Complement A (X Y) NAND (X Y) NOR (X Å Y) XNOR B Complement B 7

8
**More Logic Microoperation**

X Y F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 TABLE Truth Table for 16 Functions of Two Variables Boolean function Microoperation Name F0 = F ← Clear F1 = xy F ← A∧B AND F2 = xy’ F ← A∧B F3 = x F ← A Transfer A F4 = x’y F ← A∧B F5 = y F ← B Transfer B F6 = x y F ← A B Ex-OR F7 = x+y F ← A∨B OR Boolean function Microoperation Name F8 = (x+y)’ F ← A∨B NOR F9 = (x y)’ F ← A B Ex-NOR F10 = y’ F ← B Compl-B F11 = x+y’ F ← A∨B F12 = x’ F ← A Compl-A F13 = x’+y F ← A∨B F14 = (xy)’ F ← A∧B NAND F15 = F ← all 1’s set to all 1’s TABLE Sixteen Logic Microoperations 8

9
Insert Insert The insert operation inserts a new value into a group of bits This is done by first masking the bits and then ORing them with the required value 1) Mask ) OR A before A before B mask B insert A after mask A B A after insert AVB

10
**4-6 Shift Microoperations**

Shift example: Shift Microoperations : Shift microoperations are used for serial transfer of data Three types of shift microoperation : Logical, Circular, and Arithmetic

11
**Shift Microoperations**

Symbolic designation Description R ← shl R Shift-left register R R ← shr R Shift-right register R R ← cil R Circular shift-left register R R ← cir R Circular shift-right register R R ← ashl R Arithmetic shift-left R R ← ashr R Arithmetic shift-right R TABLE Shift Microoperations

12
**Logical Shift A logical shift transfers 0 through the serial input**

The bit transferred to the end position through the serial input is assumed to be 0 during a logical shift (Zero inserted)

13
Logical Shift Example 1. Logical shift: Transfers 0 through the serial input. R1 ¬ shl R1 Logical shift-left R2 ¬ shr R2 Logical shift-right (Example) Logical shift-left

14
Circular Shift The circular shift circulates the bits of the register around the two ends without loss of information

15
**Circular Shift Example**

Circular shift-left Circular shift-right (Example) Circular shift-left is shifted to

16
Arithmetic Shift An arithmetic shift shifts a signed binary number to the left or right An arithmetic shift-left multiplies a signed binary number by 2 An arithmetic shift-right divides the number by 2 In arithmetic shifts the sign bit receives a special treatment

17
**Arithmetic Shift Right**

Arithmetic right-shift: Rn-1 remains unchanged; Rn-2 receives Rn-1, Rn-3 receives Rn-2, so on. For a negative number, 1 is shifted from the sign bit to the right. A negative number is represented by the 2’s complement. The sign bit remained unchanged.

18
**Arithmetic Shift Right**

Example 1 0100 (4) 0010 (2) Example 2 1010 (-6) 1101 (-3)

19
**Arithmetic Shift Left The operation is same with Logic shift-left**

The only difference is you need to check overflow problem Carry out Sign bit LSB LSB Rn-1 Rn-2 0 insert Vs=1 : Overflow Vs=0 : use sign bit

20
**Arithmetic Shift Left Arithmetic Shift Left : 0010 (2) 0100 (4)**

Example 1 0010 (2) 0100 (4) Example 2 1110 (-2) 1100 (-4)

21
**Arithmetic Shift Left Arithmetic Shift Left : 0100 (4) **

Example 3 0100 (4) 1000 (overflow) Example 4 1010 (-6) 0100 (overflow)

Similar presentations

Presentation is loading. Please wait....

OK

Princess Sumaya University

Princess Sumaya University

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on branches of physics Ppt on google chrome web browser Ppt on poultry farm management Ppt on hydraulic power steering system Ppt on cross-sectional study strengths and weaknesses Ppt on network interface card Animated ppt on magnetism worksheet Ppt on password protected door lock system Ppt on history of olympics wikipedia Ppt on charge coupled device definition